Last year at the drag strip I ran consistent mid to low 14s @ 98 to 100 mph. This year I have done two mods, and my performance is significantly less. My times last weekend ranged from 14.79 to 14.98 @ 95 to 96 mph (I actually ran a 15.16 also, but I missed a shift on that one...). The only mods I have done are a cat-back and a TB airfoil from TPIS. The cat-back is Sweet Thunder's chambered system. My car loses power once it gets above 4k rpm, almost like its not getting enough of something. I can feel the motor struggling it seems. I am assuming I'm not getting enough air? My current setup is the stock (or what appears to be stock) air intake with a K&N filter. The only aftermarket air intake I could find for an LT1 Vette is the SLP system. Is there anything else out there, or does anyone have some thoughts on what my problem is? When I bought this car last year they told me it has an "upgraded cam". Despite consistent nagging and calling, they were unable to verify what kind of cam is in the car. As far as I can tell the cam seems stock or close to stock. Mileage is currently 100k.

 

it has an aftermarket cam??? i wonder if the previous owner ever got a tune after installing the cam. but it would be very hard to get an accurate pcm tune without knowing the specs of the cam. it is not an air problem...the LTx engines were designed to make their peak power above 4k rpm. i would guess either a fuel delivery problem, pcm not tuned, or maybe opti going out??? im not real familier with the LTx engines.

 

Thx. I guess regardless of what the situation is, I'm going to have to dig into the motor to find out exactly what kind of cam I have.